1. Field of the Invention
This invention relates generally to apparatus for reproducing video signals recorded in successive parallel tracks, for example, extending obliquely, on a magnetic tape by means of at least one rotary magnetic head which scans the tracks in succession at a rate dependent on the speed at which the tape is moved longitudinally by a tape transport assembly, and more particularly is directed to providing such apparatus with an improved track searching arrangement by which the tape can be accurately and rapidly positioned for scanning of a selected track by the rotary head or heads.
2. Description of the Prior Art
When an existing magnetic video tape recorder of the helical scan type (VTR) is operated in its reproducing or playback mode with a time base corrector, the speed at which the tape is transported or moved longitudinally between the supply and take-up reels may be varied while the rotary magnetic heads are rotated at the frame frequency so as to provide, on a monitor, a still, slow-motion or fast-motion reproduced picture in dependence on the speed of movement of the tape. Existing VTRs have been provided with a manually actuable control lever or knob for controlling the speed and direction of movement of the tape in dependence on the extent and direction, respectively, of the angular displacement of the control lever or knob from a neutral position at which movement of the tape is halted. A VTR provided with the foregoing so-called "joy stick" control may be used for arbitrarily selecting a particular track on the tape at which a reproducing or recording operation is to be commenced, as during editing of the tape. Although the high speed movement of the tape in one director or the other can be effectively achieved by a corresponding large angular displacement of the control lever or knob from its neutral position so as to bring a roughly desired portion of the tape to the position for scanning of the tracks thereon by the rotary heads, difficulty is experienced in using the existing joy-stick control to thereafter position a single selected track for scanning by the rotary heads, as for still-picture reproduction or for the commencement of an editing operation, or when a sequence of still pictures are to be reproduced one after the other at a slow rate. Since the joy-stick control only controls the speed at which the tape is moved in dependence on the angular displacement of the control lever or knob from its neutral position, repeated to and fro displacements of the control lever or knob are required to dispose a selected track for scanning by the rotary heads and, even then, it is difficult to stop the tape with the selected track precisely positioned for scanning by the heads.